Digest::BubbleBabble takes a message digest (generated by either
of the MD5 or SHA-1 message digest algorithms) and creates a
fingerprint of that digest in "bubble babble" format.  Bubble babble
is a method of representing a message digest as a string of "real"
words, to make the fingerprint easier to remember. The "words" are
not necessarily real words, but they look more like words than a
string of hex characters.
